Taking aim at the dominance of Apple Computer, Microsoft this week is launching a test version of a revamped jukebox aimed at trying to knock iTunes down a peg.

Microsoft plans to make the beta of Windows Media Player 11 available for free to Windows XP users on Wednesday, but some consumers got an earlier look by scooping up a portable device optimized for the new jukebox.

The new media player is Microsoft's latest attempt to unseat Apple, whose sales of both music and digital music players have consistently outpaced those of competitors.

Microsoft says despite Apple's big lead, the competition for online music supremacy isn't nearly over. Redmond's strategy is to attract the enormous number of people who have yet to buy a digital music player, says Geoff Harris, product unit manager for Windows Media Player.

"Remember the digital market represents only 5 percent of the total market," Harris said "That means that 95 percent are still buying in traditional means. At the end of the day, this (segment) is still in its infancy."

Although the official launch of the media player beta isn't expected until Wednesday, consumers could find the software inside iRiver's Clix digital music player, which went on sale Monday.

For this go-round at challenging the tight grip that Apple's iTunes and iPod have on the music market, Microsoft is trying a swarm approach, choosing to partner with powers inside the music industry--aiming to offer a hipper alternative than it has in the past--as well as with hardware manufacturers. The software company has teamed with music icon MTV and its new subscription online music service, called Urge, to help attract fans. Urge was available on Monday, but it won't make an official debut until Wednesday.

The partnership with MTV is not exclusive. Microsoft's software will also work with music services MSN Music and Napster and will be featured in several other devices, including those made by Samsung and Creative. And although this is Microsoft's attempt to have services, software and players that more easily work with one another, it still doesn't work with the leading player--Apple's iPod.

WMP 11 will be available both for Windows XP and Vista, but on different timetables.

The beta that Microsoft is making available for download on Wednesday is of Windows Media Player 11 for Windows XP. Windows Media Player 11 has been in beta testing--as part of Windows Vista--for several months, though until Monday, the Urge service has not been available.

WMP 11 has, so far, received favorable reviews (click here for comments from CNET.com). And even though it doesn't work with the iPod, WMP 11 includes several features to help it compete with iTunes.

First, the software is designed to make it easier to scroll through long music libraries. WMP 11 identifies music with photos of album covers. On iTunes, music lists are identified by text only, meaning a user must wade through long blocks of type.

The software also includes a sort of gas gauge that indicates visually how much room is left on a portable player for additional music.

MTV's Urge is integrated into WMP 11 and offers more than 2 million songs, which are available for 99 cents apiece. Users also have two subscription-service options, one priced at $9.95, the other at $14.95.

The software will also be included in the Windows Vista operating system, due to launch next year. The final version of WMP 11 is due to ship later this year.